Finding a new function given a composite function (Case B : Second function is given) Example 1 October 5, 2017January 20, 2014 by Example 1 (substitution Method) A function f is defined by $f:x\mapsto x+2$ . Find the function g if $gf:x\mapsto {x}^{2}+3x+5$ . [Note : Second function is given, use substitution y=x+2]